Method for hydraulically displacing well materials



Jan. 27, 1953 W. A. MAXWELL ET AL METHOD `FOR HYDRAULCALLY DISPLACINGWELL. MATERIALS Filed May 5, 1947 geni/ FOM INVENTORS um M HIJ-MrPatented Jan. 27, 1953 IVIETHGD FR HYDRAULICALLY DISPLAC- ING WELLMATERIALS Wilber A. Maxwell, Houston, Tex., and .lohn A. Engstrand, LosAngeles, Calif., assignors to Grant Oil Tool Company, Los Angeles,Calif., a corporation of California Application May 5, 1947, Serial No.746,039

(Cl. 29e- 86) Si Claims.

This invention relates to improved methods for-the'displacement orrecovery of solid materials and bodies in oil wells, and having as ageneral mode of operation such displacement or recovery by the creationof a iiuid surge resulting from the Vopening of a low pressure chamberin communication with the displacement zone. The typical apparatusherein described as adapted for carrying out the present process isclaimed in our co-pending application Ser. No. 746,038,

Heretofore this same type of operation has been extensively `employed inthe use of suctiontype bailers and cleaners in various forms utilizingnormally closed chambers lowered within the hydrostatic well uid columnto the 1bottom of the well or to the location at which solids are to bedisplaced, the chambers having closures adapted to be suddenly opened toadmit to the chambers hydraulic material displacing surges which occurunder pressures corresponding to the hydrostatic head of the well liquidcolumn standing above the displacement zone at which the chamber inletordinarily is located. In instances where the extent of the hydrostaticcolumn above the displacement is great, the differential between thehydrostatic and empty charge receiving chamber pressures arecorrespondingly great, the result being that when the chamber issuddenly opened, the responsive fluid now or surge into the chamberoccurs with considerable violence. Now it has been found that themagnitude and violence of such surges are frequently so great as tocreate seriously undesirable disturbances in the well, such as thedisplacement of excessive quantities of sand into the Well, collapsingof weak casing s Heretofore. such con- 'l or liners. and like effects.sequences have been unavoidable for the reason that the hydrostaticcolumn-chamber pressure diiierential and the fluid iiow or surgeproportionate to that differential have been xed because thedisplacement zone and the chamber inlet have been under virtually thesame hydrostatic pressure, and the chamber constitutes a closed emptyzone under atmospheric pressure.

The primary object of the present invention is to avoid theabovementioned consequences of violent pressure surges in thedisplacement or recovery of solid materials from a well, by providingfor the maintenance of any desired differential between the chamberpressure and the hydrostatic displacement zone pressure, and in so doingto diminish to whatever extent desired the violence of the surge thatwould ordinarily occur at the displacement zone depth employing theconventional methods and equipment.

Specifically the invention contemplates certain novel methods wherebyeither or both the chargereceiving chamber and hydrostatic head of thewell liquid tending to enter the chamber, may be varied to give whateverdifferential is desired. In accordance with one adaptation of theinvention, the chamber may be positioned above the displacement zone adistance sufciently remote therefrom that the effective hydrostaticpressure of the iiuid tending to enter the chamber will be less than thehydrostatic pressure on the displacing zone, to a degree such that whenthe chamber is opened, the consequent liquid iii-surge will have nogreater activity or violence than necessary for movement of solids inthe displacement zone, Thus the effective column-chamber pressuredifferential may be selected or predetermined as desired to createsufficient surge for displacement of the solids, while insuring againsta surge violence productive of adverse results.

Instead of, or in addition to such selection or predetermination of thehydrostatic column pressure with relation to the chamber pressure, thepressure inside the chamber may be predetermined or controlled asdesired, by subjecting the chamber internally to the pressure of a'hydrostatic column inside a pipe string carrying the chamber. Thus byplacing the chamber in communication with the top of the well throughthe pipe string, liquid may be put into the string to establish acontrollably variable head which in turn establishes the chamberpressure and the differential between that pressure and the effectivepressure of the hydrostatic column of the well.

The invention further contemplates the retention and recovery of solidmaterials carried by the surge in the displacement Zone, all in a mannerpermitting removal of such solids from the well.

Furtherobjects and details of the invention will be understood from thefollowing description of the method as carried out by use of the typicalforms of apparatus shown by the accompanying drawing, in which:

Fig. l is a View showing the apparatus in elevation within a well;

Figs. 2 and 3 are enlarged vertical sections tal:- en respectively onlines 2-2 and 3 3 `of Fig. 1; and

Fig. 4 is a cross-section on line 4;-4 of Fig. 2.

The apparatus comprises a pipe string run into the well bore l0 andincluding a lower section l I and a relatively vertically movable uppersection I 2 extending openly to the ground surface. As will appear, theupper section of the pipe string, or at least the lower portion thereof,may constitute a closed low pressure chamber communicable with a lowerzone at which the displacement of material is to be effected. Accordingto one method of operation, the chamber may be so positioned in the wellthat the eifective pressure of the hydrostatic well iiuid column tendingto enter the chamber upon its opening, may be any amount less than thehydrostatic column pressure at the displacement zone, depending upon thedepth at which the chamber opening, i. e. the bottom portion of the pipestring section I2, is positioned in the well. Thus it will be understoodthat the well bore may contain a hydrostatic column extending above thebottom portion of the pipe string section I2, and that the length of thelatter may be varied as desired, to give any predetermined or selectedpressure differential inside and outside the low pressure chamber I3when the latter is opened. The displacement zone I4 is shown to be atthe bottom of the well, and may be assumed to contain displaceablesolids of any character, and particularly metallic or other objectsretrievable in a so-called junk basket type of fishing tool, for removalto the ground surface.

The pipe string sections Il and I2 are shown to be interconnected by atelescopic joint assembly, generally indicated at I5, including aclosure for the bottom of the chamber I3, and means operable by relativevertical movements of the sections to open the closure. Referring toFig. 2, section I2 is connected by tubular coupling I6 and the threadedjoint at I1 witha sleeve I 8, the latter having a counterbore I9 formingan annular shoulder 29. In the broad contemplation of the invention, thechamber I3 may have any suitable type of bottom closure 2I capable ofbeing opened by manipulation of the pipe string to admit well fiuid tothe chamber. As illustrative, the closure is shown to consist of afrangible disc 22 confined between gaskets 23 by a bushing 24 screwedinto the lower threaded end of the coupling I6, the bushing having afrustro-conical surface 25.

Sleeve I8 is connected with the top coupling end 26 of the lower pipestring section II by a tubular mandrel 21 threaded at 28 into thecoupling and having splines 29 extending through ways 30 in the sleeve,see Fig. 4, the splines permitting transmission of rotation from theupper to the lower string section, as for turning the fishing tool intothe bottom sand. The mandrel 21 has an enlarged diameter disc breakerhead 3| engageable against shoulder 20 to suspend the string sectionbelow, and containing one or more lateral openings 32 through whichfiuid may pass upwardly from section II into the space 33. Head 3I maycarry the O type seal rings SII to prevent fluid leakage along the head.Upon downward movement of the upper section I2 relative to the lowersection II, the disc 22 is fractured by impact against the pointedbreaker head 3Ia, relative movement of the breaker toward the disc beinglimited by engagement of the lower end of the coupling with tool joint26. Full opening of the chamber inlet may be effected by raising theseat 25 from the breaker after the disc is ruptured. In order to assurequick and complete rupturing of the disc, impacting of the latteragainst the breaker may bc caused to occur under substantial load fromabove, as by using a shear pin 35 projecting into and engageable withthe end of the mandrel recess 36 until the superposed load issufficiently great to shear the pin, at which point the disc is suddenlydropped against the breaker.

The lower string section II may carry any suitable form of tool adaptedto receive and retain solids displaced from the zone I4, as a result ofan upward fluid surge created by opening the chamber I3. Typically thetool 36 is shown to comprise a tubular body 31 connected by coupling 38to the pipe string and having a bottom coring edge 39 capable ofpenetrating the sand in the bottom of the well. The body may contain oneor more sets of retainers, such as the circular arrangement of radiallydeilectible ngers 40 shown in Fig. 3, past which the solids are carriedupwardly by the fluid surge to thereafter be retained by the fingerassembly.

Suitable provision may be made for venting gas or air from the top ofthe lower pipe string section II as the latter is run down through thehydrostatic column, as by means of a valvular gas release preventingrin-flow to the string when the low pressure chamber is opened. Referringto Fig. 2, coupling 26 may contain a pressure release, generallyindicated at 40 comprising a ball valve 4I contained in bore 42 andseating against shoulder 43 to control the gas escape from the stringsection II through passages 44 and 45. Opening of the valve is resistedby coil spring 45, the compressive force of which is adjustable by plug41 to maintain any desired seating thrust against the valve. Asillustrative, the pressure release may be set to permit opening of thevalve at a gas pressure of around lbs. per

sq. 1n.

According to one mode of operation, the apparatus is run into the wellin the condition illustrated in Figs. l and 2, with the connection I5located at a remote elevation above the displacement zone I4. Asillustrative, depending upon the desired pressure differentialconditions, the low pressure chamber inlet 48 may be located in excessof 500 to 1000 feet above the displacement zone. As the equipment islowered down through the hydrostatic column of well fluid, the lattermay be permitted to rise Within the lower string section II to theheight of the disc 22 (when the latter is lowered below the top of thehydrostatic column) because of the capacity of the pressure release 40to open and vent gas or air from the lower string section. Assuming thetool 36 to be bottomed in the sand, downward movement of the upperstring section I2 causes the disc to be impacted and ruptured againstthe breaker head, as described, whereupon the chamber I3 is opened toadmit a high velocity surge of well fluid from the displacement zone I 4upwardly through the lower string section. As will be understood,however, the effective pressure differential under which the fluidenters the chamber, is the difierence between the normal internalpressure of the chamber and the hydrostatic pressure of the well fluidcolumn standing above the chamber inlet. Thus, though directlycommunicated to the displacement zone IA, the action or magnitude of thesurge will be far less than that which ordinarily results from theopening of a chamber at the depth of the displacement zone and withconsequent excessive disturbances in the well.

In accordance with a variational method, the pressure differentialcausing flow into the pressure chamber, vmay be varied as desired, andwithin wide limits, by controlling the chamber pressure, with or'withoutvariation from the vdisplacement zone pressure of the hydrostatic fluidpressure tending to enter the chamber. For this purpose iiuid may beintroduced to the upper pipe string section to maintain whatever chamberpressure desired at the time the chamber is opened. Thus circulating mudor other liquid may be lled into the upper section l2 to a depthimposing the desired pressure at the chamber side of the disc. Since bythis method the difierential flow creating pressure is controllableindependently of the hydrostatic well pressure at the chamber inlet, thelatter, including the joint assembly I5, may be placed at any depth inthe well, including that of the displacement zone le in which event thechamber closure may be directly above the tool 3S. In general, thedesired pressure diiierential may be established by relating anyselected chamber pressure to the effec tive outside hydrostatic pressureas determined by the depth at which the chamber inlet is positioned.

We claim:

1. The method of displacing material at a bottom location in a wellcontaining a hydrostatic column, that includes lowering in the well andsaid column a low pressure chamber comprising a vertical string of pipestands closed against reception of the column liquidl and communicablethrough a passage with the top of the well, in-

troducing liquid to said passage to form a liquid column in the chamberextending vertically through a large number of said pipe stands and of aheight to maintain inside and outside of the chamber unbalancedhydrostatic column pressures the differential of which is substantiallyless than the pressure of the hydrostatic well column pressure at saidlocation, and then suddenly admitting well fluid to the chamber tocreate a liquid surge from said location.

2. The method of displacing material at a bottom location in a wellcontaining a hydrostatic column, that includes lowering in the well andsaid column a low pressure chamber comprising a vertical string of pipestands closed against reception -oi the column liquid and communicablethrough a passage with the top of the well, introducing liquid to saidpassage to form a liquid column in the chamber extending verticallythrough a large number of said pipe stands and of a height to maintaininside and outside of the chamber unbalanced hydrostatic columnpressures the diierential of which is substantially less than thepressure of the hydrostatic well column pressure at said location, thensuddenly admitting well fluid to the chamber to create a liquid surgefrom said location, and entrapping and recovering for removal from thewell solids displaced by the liquid surge.

3. rlhe method yof displacing material at a location in a wellcontaining a hydrostatic column, that includes lowering into the well anextended tubular string comprising a vertical series of pipe standscommunicating at a lower portion of the string with said location andcontaining a closure acting to prevent fluid flow upwardly from saidlocation beyond a predetermined point in the string, maintaining acolumn of liquid in said string of a height substantial as compared withbut less than the height of the well column and extending verticallythrough a large number of said pipe stands so that the diiierentialbetween the well column pressure and the pressure at the inside of thestring is substantially less than the hydrostatic pressure of the wellcolumn at said location, and then opening said closure to create aliquid surge from said location upwardly within the string.

4. The method of displacing material at a location in a well containinga hydrostatic column, that includes lowering into the weil an extendedtubular string comprising a vertical series of pipe stands communicatingat a lower portion of the string with said location and containing aclosure acting to prevent fluid iiow upwardly from said location beyonda predetermined point in the string, maintaining a column of liquid insaid string or" a height less than the well column but at least about500 feet and extending vertically through a large number of said pipestands, so that the differential between the well column pressure andthe pressure at the inside of the string is substantially less than thehydrostatic pressure of the well column at said location, and thenopening said closure to create a liquid surge from said locationupwardly within the string.

5. The method of displacing material at a location in a well containinga hydrostatic column, that includes lowering into the well an extendedtubular string comprising a vertical series of pipe stands communicatingat a lower portion of the string with said location and containing aclosure remotely above said location preventing upward fluid flow withinthe string beyond a predetermined point, maintaining a column of liquidin said string beneath said closure of a height substantial as comparedwith but less than the height of the well column and extendingvertically through a large number of said pipe stands so that thediilerential between the well column pressure and the pressure at theinside of the string is substantially less than the hydrostatic pressureof the well column at said location, and then opening said closure tocreate a liquid surge from said location upwardly with the string.

6. The method of displacing material at a location in a well containinga hydrostatic column, that includes lowering into the well an extendedtubular string comprising a Vertical series of pipe stands communicatingat a lower portion of the string with said location and containing aclosure near said location acting to prevent iiuid flow upwardly withinthe string from said location, maintaining a column of liquid in saidstring beneath said closure of a height substantial as compared with butless than the height of the well column and extending vertically througha large number of said pipe stands so that the differential between thewell column pressure and the pressure at the inside of the string issubstantially less than the hydrostatic pressure of the well column atsaid location, and then opening said closure to create a liquid surgefrom said location upwardly within the string.

7. The method or" displacing material at a location in a well containinga hydrostatic column, that includes lowering into the well an extendedtubular string comprising a vertical series of pipe stands communicatingat a lower portion of the string with said location and containing aclosure acting to prevent fluid iiow upwardly from said location beyonda predetermined point in the string, maintaining a column of liquid insaid string of a height substantial as compared with but less than theheight of the well column and extending vertically through a largenumber of said pipe stands so that the differential between the wellcolumn pressure and the pressure at the inside of the string issubstantially less than the hydrostatic pressure of the well column atsaid location, then opening said closure to create a liquid surge fromsaid location upwardly within the string, and recovering for removalfrom the well solids displaced at said location by the surge.

8. The method of displacing material at a location in a Well containinga hydrostatic column, that includes lowering into the Well an extendedtubular string comprising a vertical series of pipe stands communicatingat a lower portion of the string with said location and containing aclosure acting to prevent fluid flow upwardly from said location beyonda predetermined point in the string, maintaining a column of liquid insaid string of a height substantial as compared with but less than theheight of the well column and extending vertically through a largenumber of said pipe stands so that the diierential between the wellcolumn pressure and the pressure at the inside of the string issubstantially less than the hydrostatic pressure of the Well column atsaid location, then opening said closure to create a liquid surge fromsaid location upwardly within the string, entrapping in said stringsolid material carried thereinto by the fluid surge, and draining thefluid from the string downwardly about said solid materials.

9. The method of displacing material at a location in a well containinga hydrostatic column, that includes lowering into the well an extendedtubular string comprising a vertical series of pipe stands communicatingat a lower portion of the string with said location and containing arupturable closure acting to prevent fluid flow upwardly from saidlocation beyond a predetermined point in the string, maintaining acolumn of liquid in said string of a height substantial as compared withbut less than the height of the well column and extending verticallythrough a large number of said pipe stands so that the differentialbetween the well column pressure and the pressure at the inside of thestring is substantially less than the hydrostatic pressure of the wellcolumn at said location, and then rupturing said closure to create asudden liquid surge from said location upwardly within the string.

WILBER A. MAXWELL.

JOHN A. ENGSTRAND.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 1,777,581 Salveson Oct. 7, 19301,968,282 Cavins July 31, 1934 2,090,616 Erwin Aug. 24, 1937 2,118,458Cavins May 24, 1938 2,169,922 Notley Aug. 15, 1939 2,384,090 HartsellSept. 4, 1945

